Researchers at Dartmouth have produced a promising new cancer treatment--a personalized vaccine developed from the patient's own tumor.
The study examines patients with colorectal cancer. Dr. Richard Barth, a Dartmouth surgeon and the author of the study, operated on 26 patients whose colorectal cancer had metastasized to the liver. In such a situation, patients are expected to die from tiny undetectable metastases that escape the surgeon's scalpel.
But here's where Barth and his colleagues tried something different. They took proteins from the patient's tumor and mixed them with a certain kind of cell grown from the patient's blood. The personalized vaccines were injected into each patient a month after surgery. Barth was able to determine that about 60% of the patients developed an immune response from the vaccine.
About five years later, he was able to compare the clinical outcomes between those who had had an immune response, and those who had not. Of the group who did not have an immune response from the vaccine, only 18% were alive and tumor-free. Of the group who did have an immune response from the vaccine, 63% were alive and tumor-free--a remarkable result indeed. (The vaccine approach has the added benefit of being non-toxic, in contrast to chemo.)
The results were published this week in the journal Clinical Cancer Research. This is not the first time doctors have tried to fight fire with fire (or rather, tumor with tumor). Barth has been trying it on mice and humans for over a decade. And other clinical researchers had tried it as well--but without much success. Researchers were hoping that tumor-derived vaccines could actually attack and kill fully-grown tumors, rather than the microscopic metastases.
"It turned out we were asking the T-cells to do too much," Barth said in a press release, referring to the type of white blood cell active in an immune response. "The small number of T-cells generated by a vaccine can't destroy a large tumor. However, what they may be able to do is search out and destroy tumor cells that exist as only microscopic deposits. Once we brought patients into a measurable tumor-free condition with surgery, the anti-tumor T-cells induced by the vaccine may help keep them that way."
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